jellies



March 24, 1964 D. A. JELLIES DISK-{WASHING APPARATUS INVENTOR. DAVID A JELLIES BY 2 Sheets-Sheet 1 ATTORNEY Filed Dec. 8, 1961 March 24, 1964 D. A. JELLIES 3,126,024

DISHWASHING APPARATUS Filed Dec. 8, 1961 2 Sheets-Sheet 2 1. 5| 6? r-w FIG. 6 s2 j 64 53 i 65 Z (INSULATION) FIG. 7

n5 VAC so c MOTOR MOTOR AT INVENTOR. DAVID A JELLIES IDLING FULL LOAD MOTOR LOAD IN WATTS rm/WE United States Patent 3,126,024 DISHWASNING APPARATU David A. Jellies, flccnomowoc, Wis, assignor to General Electric Qnmpany, a corporation oiNew York Filed Dec. 8, 1961, Ser. No. 158,063 12 Claims. (61. 134-57) This invention relates to dishwashing apparatus of the type in which the articles to be washed are subjected to a timed schedule including washing, rinsing and drying operations; and in particular, the invention relates to means whereby the several phases of the complete operational cycle may be timed without conventional time-clock operated switches.

Domestic automatic dishwashers have hitherto employed control mechanisms and methods of operation which require that the main operational motor be started and stopped several times during the operational cycle. Such motors must have relatively high starting torque, and are usually of the capacitor-start, split-phase induction type; it is not unusual also to provide control means for reversing the motor to operate a direction responsive pump to evacuate the spent washing and rinsing liquids.

in application Serial No. 145,224, in which I am an applicant jointly with John D. Seal, said application being assigned to my assignee herein, there is disclosed means to conjointly operate the wash water circulation pump and the wash water discharge pump by an electric motor of the shaded-pole type which runs continuously during the sequence of washing and rinsing operations. It is well known that although this type of motor is much lower in cost than split-phase induction motors, it is so deficient in starting torque, and so relatively inefiicient electrically, as to have been considered incapable of use in dishwashing apparatus. We found, however, that by arranging the dishWashing cycle so that the motor starts under no-load conditions and runs uninterruptedly throughout the entire sequence of washing and rinsing operations, we can use a shaded-pole motor efiectively.

In accordance with the present invention, I arrange a fan or blower to circulate air over the motor to cool the same during use, and by a suitable ducting system introduce this air, which will have accumulated substantial heat, into the interior of the dishwasher to facilitate the drying of the dishes therein. In said application S.N. 145,224, motor operation is terminated following the final rinsing operation; the present invention provides a supplementary motor energizing circuit which continues the motor in operation 'tmtil the temperature of the air measured at a suitable point in the ducting system drops to a predetermined value, whereupon the motor circuit is interrupted to signify the completion of the washing, rinsing and drying sequence.

It is therefore, a principal object of the invention to provide in a dishwasher powered by an electric motor of the shaded-pole type, a dish drying cycle utilizing the otherwise wasted heat energy of the motor as the heat source for the dish drying medium.

It is another object of the invention to provide means for heating the dishes within a dishwasher tub, prior to the introduction of water thereinto.

In the accompanying drawings,

FIG. 1 is a front elevation of a dishwasher embodying my invention, with the lower part of the tub shown in section and the machinery compartment open to disclose a typical arrangement of the motor and its accessories;

FIG. 2 is a fragmentary sectional elevation of the upper portion of the rear of the dishwasher tub and its enclosing cabinet to show a means for venting the tub interior;

'FIG. 3 is a plan view of the motor and the pump assembly taken in section on lines 3-3 of FIG. 1 and 3,125,024 Patented Mar. 24, 1964 with the air duct about the motor partially broken away;

FIGS. 4 and 5 respectively are sectional elevations taken on lines 4-4 and 5-5 of MG. 3;

FIG. 6 is a somewhat schematic showing of a stepping switch useful with the present invention;

7 is a typical circuit diagram; and

FIG. 8 is a graph showing the relation of motor casing temperature in degrees Fahrenheit to the motor load expressed in watts.

Referring now to FIG. 1, a dishwasher 1 includes a cabinet 2 within which is appropriately secured a tub 3 adapted to contain the dishes and other articles to be washed. Although the arrangement of the loading door is not important to the present invention, the dishwasher has been shown as having a conventional front door 4 which is hinged at its bottom (not shown) whereby the door may be swung from its illustrated closed position to a substantially horizontal open position. It will be understood that the tub 3 has an open front whereupon when the door is in its open position, the interior of the cabinet is exposed for the loading or removal of dishes. Pursuant to presently conventional practices there are mounted at two appropriate levels along the side walls of the tub 3, horizontally disposed guide rails (not shown) which slidably accommodate the racks (not shown) in which the dishes and other articles are placed. Pursuant to this well-known arrangement, when the door 4 is open the racks may be withdrawn from the tub to make them readily available for loading or unloading the dishes.

As indicated in FIG. 2, the rear wall of the tub near its top, may be provided with a ventilation opening 5 adjacent an opening 6 in the rear Wall of the cabinet 2. To prevent the splashing or otherwise unwanted escape of washing liquid through said opening I provide a channel-shaped baille 7 about which air may pass to the exterior of the cabinet as suggested by the arrowed line in FIG. 2.

The tub 3 is arranged within the cabinet so as to provide a substantial machinery space 8 below the bottom of the tub. It will be noted that the bottom wall of the tub slopes to provide a sump 10 characterized by a preferably horizontal bottom wall 11. A standpipe 12 rotatably receives at its upper end a rotor 14 having a suitable arrangement of apertures 15- to discharge washing and rinsing liquid into the tub, whereby the articles being washed therein are subjected to sprays of washing liquid. Reaction discharge orifices 16 are placed in opposite side walls of the rotor; as is well known, the issuance of the liquid from side wall jets 16 will cause the rotor 14 to spin. Water is introduced into the tub 3- by way of a conventional solenoid actuated valve 17 which is connected to a source of heated water (not shown) such as the domestic hot water piping oi the residence or other establishment in which the dishwasher is installed. The valve discharge line 18 communicates with any suitable fitting (not shown) discharging through the side or top wall of the tub. Solenoid valves of this type are ordinarily normally closed and require that the solenoid coil (shown schematically in FIG. 7) be energized to permit flow of water into the tub as later explained. The washing and rinsing liquid is recirculated among the dishes and other articles by means of a centrifugal pump '20 having its inlet fitting communicating with the sump 11 through a screened inlet port 21, and having its discharge port 22 communicating directly with the standpipe l2, whereupon the rotor 14 is supplied with liquid under suitable pressure and spins to cause the forceful distribution of liquid within the tub. To evacuate the spent washing or rinsing liquid from the tub, I utilize an inlet fitting 23 communicating with a drain pipe 24 connected to a discharge pump 25'. The said fitting 23 embodies a siphon or other device (not shown) whereby liquid will not flow from the tub 3 into the pipe 24 until the fitting 23 has been submerged. Once flow into the pipe 24 begins, however, flow continues until substantially all of the liquid has been evacuated from the tub 3. Typical forms of such inlet fittings are disclosed in the above-noted application, Serial No. 145,224.

It will be understood that the pumps 26 and are of the centrifugal type and that they are mounted on the respective opposite ends of a motor shaft 28 extending from the motor 30 as indicated in FIG. 3. To prevent the pump inlet system from becoming air-locked I utilize a vent tube 31 which, of course, will extend to an elevation substantially above the maximum free water level within the tub 3.

The motor 30 is of the shaded-pole type. It is well known that motors of this type are inefficient, and that as much as 75% of the electrical energy input to said motor is converted to heat. It is therefore necessary to provide means for abstracting said heat continuously during the operation of the motor. The present invention provides for utilizing this otherwise waste heat as a medium for heating the dishes prior to the first washing operation, and for drying the dishes after the final rinsing operation. As shown in FIGS. 1 and 3, I provide an air fan 33 intermediate the motor and the pump 20. Said fan comprises a blower wheel 34 of the conventional Sirocco type mounted directly on the motor shaft 28 and contained within a housing 35 defining an axial inlet opening 36 and a tangential discharge duct 37. The fan is, therefore, part of an air flow system in which the duct 37 directly communicates with a duct 33 suitably positioned within the dishwasher tub 3. Said duct 38 is provided with any suitable cap 40 which guards against the inflow of liquid into the duct while providing for the relatively free passage of air into the dishwasher tub. In other words, the open end of the duct 38 is suitably above the maximum level to which water may accumulate in the tub, and the cap 40 guards against droplets or streams of water from the dishes or the rotor .14 from entering. As part of the air flow system I include the discharge duct 5, and a shroud or air duct 41 about the motor 30. The latter duct enforces a flow of air over the exterior of the motor for substantially its full length. Preferably, air flow over the motor should be turbulent, and as indicated in FIG. 5, the shroud 41 is dimpled, as at 42, so as to create the turbulence without imposing undue restriction on the air flow.

Reference is now made to FIG. 6 which schematically represents a steppingswitch by means of which the washing and rinsing operations of the dishwasher are established. The discharge line 43 from the discharge pump 25 is provided with the stepping switch assembly 4 4 of which a body portion 45 is suitably installed in the line 43. It will be understood that discharge line 43 rises to a point of discharge into an adjacent plumbing waste line (not shown) or other waste-line-connected facility disposed at a level substantially above the maximum level of liquid within the tub 3. The body portion 45 of the stepping-switch mechanism is provided with a diaphragm 46 directly exposed to the pressure of liquid within the body; said diaphragm may be advantageously secured to the body by means of a suitably ventilated cap 47 mounted on a peripheral body flange. An upstanding leg 48 of a support 50 pivotally mounts the actuating lever 51 of a conventional escapement mechanism which includes the U-shaped structure 52 having legs 53 and 54 straddling a ratchet wheel 55 rotatably mounted in bearing members 56 extending upward-1y from the support 50. The legs 53 and 54 are adapted to engage with ratchet teeth, such as the teeth 57, 58 of ratchet wheel 55, it being understood that there are a plurality of said teeth as neces sary to accomplish a one-half rotation of the ratchet wheel in a desired number of operations of the escapement lever. It will be noted that leg 53 is longer than leg 54.

The escapement structure 52 is rockably mounted in the lever 51 and is biased by any suitable leaf spring (not shown) to rotate in a direction counterclockwise of FIG. 6. As lever 51 is rotated upwardly, therefore, leg 53 will disengage from one ratchet tooth and snap into engagement with the next higher tooth; on the downward movement of the lever the leg 53 will rotate the ratchet wheel until such rotation is interrupted by the engagement of leg '54 with a ratchet tooth. As is well understood in the art, this rotation of the ratchet wheel is therefore in a toothby-tooth manner.

The upward movement of lever 51 is accomplished by a push rod 6%} fixed to the diaphragm 46 and extending freely through the cap 47 and support 50 to bear against the underside of the lever. Any suitable stop means (not shown) may be employed to limit the upward and downward movement. As diaphragm 46 is displaced upwardly under pressure conditions in body 45 later described, lever 51 will be rotated in counterclockwise direction against the return bias of the spring 59 which extends from lever 51 to the support 50.

The function of the ratchet mechanism is to operate switching devices to establish or interrupt circuits in the motor and the solenoid energy systems. The ratchet wheel, therefore, has directly associated with it a cam 61 having a cylindrical body and two diametrically opposed lobes 62, 62.1. The body portion is concentric with the ratchet wheel 55 and, in fact, the ratchet wheel and cam are advantageously integral, being formed from a moldable insulation material such as nylon. It will be observed that the cam 61 is to the rear of ratchet wheel 55 as viewed in FIG. 6.

A bracket 63 which may be a part of support structure 50 mounts an insulation block 64 to which is rigidly secured a fixed contact arm 65 and a springable contact arm 66, each being provided with suitable contact buttons as shown. Contact arm 66 is shaped to have a cam follower 67 and is inherently biased to move to a closed circuit condition when the follower disengages from the lobe 62 and rides on the cylindrical body of the cam. Of course, the elements 65 and 66 are rearward of the ratchet lever 51 and are not in operational interference therewith. Insulation block 64 also mounts contact springs 68, 70 biased so as normally to close their respective contacts. An actuating arm 71 mounted on contact arm 66 has an insulating tip which extends rearwardly under contact spring 68, but is at all times clear of spring 70, whereupon when contact arm 66 lifts by way of the engagement therewith of a cam lobe 62 or 62.1, the actuating arm 71 separates the contact spring 68 from spring 70 to disengage the contacts thereof.

Briefly stated, for the control of the dishwasher washing and rinsing functions forms part of the invention in application Serial No. 145,224, the operation of the dishwasher is as follows:

When the user loads dishes into the dishwasher and places the required detergent therein, he closes the door and latches it home by means of the latch 72. Said latch is preferably of the type disclosed and claimed in my Patent 3,005,065, patented October 17, 1961, for Domestic Appliance, and assigned to my present assignee. The operation of said latch closes a line switch such as the switch 73, FIG. 7, which prepares the circuit for energizing the motor and solenoid. The circuit is not complete at this stage, for cam follower 67 of switch spring 66 is on lobe 62 of cam 61 and the circuit is therefore open at this point. Spring contacts 68 and 70 are also open. Then by means such as a manual actuation button 75 on the dishwasher cabinet, said button being mechanically associated with the lever 51 by means such as the wire 76, the lever 51 is physically lifted and then released, whereupon the ratchet Wheel and the cam are rotated one step in a counterclockwise direction. This permits the cam follower to move to the cylindrical body portion of cam 61 and thereby to complete the obvious circuit to energize the winding of motor 30" and the solenoid coil 77 of the valve 17. The motor starts under a no-load condition and quickly attains operational speed. The valve 17 is at this time open to admit water into the tub, and after an interval determined by the rate of flow through valve .17, the pump 24 is supplied with wash Water through the inlet 21. However, because thepump has substantial capacity, there is a further intenval before water is received by the pump in suflicient quantity to effectively actuate rotor 14, whereupon washingbegins. The pump 25 does not receive liquid until the free level of liquid in the tub attains the level necessary to etfect siphonic flow through the inlet system of the discharge'pump 25. Water continues to flow into the tub through valve 17 but the pump-out rate greatly exceeds the inflow rate and the tub is quickly evacuated. The pressure in discharge line 43 is exerted against diaphragm 46, lifting the diaphragm and the push rod st to rock lever 51 upwardly. This movement of lever 51 cooks the escapement mechanism. At the completion of the pump-out operation the pressure in the discharge line subsides to the degree which permits spring 61 to move the lever 51 downwardly (thus displacing diaphragm 46 downwardly, also), whereupon the escapement mechanism rotates the ratchet and cam another step. The valve 17 continues to admit liquid to the tub, but the siphonic flow to the pump inlet will have been broken due to air flow into the discharge system as the pump completes the evacuation. The tub then fills for a second washing operation. The action is repeated until the lobe 62.1 engages the cam follower 67 to interrupt the power circuit for the motor and the solenoid; at this stage of operation, the dishwasher will have accomplished two washing and two rinsing operations, each with hot water.

The final rinsing action, which includes the evacuation of the rinse water before cam lobe 62.1 opens the motor circuit, should preface the beginning of the dish drying operation. Therefore, the motor 30 must remain in operation to effect a translation of heated air over the rinsed dishes.

It has previously been noted that motors of the shadedpole type are electrically inefiicient and that as much as 75% of the electrical energy input is Wasted as heat. As is graphically portrayed in FIG. 8, the motor in idlingthat is to say, subjected only to the load imposed by the fan 33-draws about 185 watts which represents a motor temperaturethat is, a temperature of the windings, field stack, etc.of about 165 Fahrenheit. At full load, representing water circulation and fan operation, the motor draws about 325 watts, with a resulting temperature of about 210 Fahrenheit.

It has been previously noted that the fan 33 and the shroud 41 are arranged for efficiently abstracting heat from the motor 39 and that the heated, discharged air from the fan is piped into the tub 3 by way of the duct 38. At the commencement of a dishwashing operation the dishes and other articles are at room temperature, and as such are cold as respects the incoming hot water. In the usual domestic dishwasher the cold dishes abstract heat from the water, with the result that the first washing operation is carried out at a lower temperature than may be desirable. In a dishwasher incorporating the present invention, however, the discharge of heated air into the tub raises the temperature of the dishes before there is any substantial amount of contact of water with the dishes, thus reducing the temperature drop of the water during this first operational period. The heating effect of the air flow continues throughout the washing and rinsing operations.

I provide for continued operation of the motor to generate heat and air movement for drying the dishes by means of a thermostat 80, FIG. 7, in a circuit which bypasses contacts 65 and 66. This thermostat may be of the bimetal type, calibrated to close at about 180 Fahrenheit and to open at about 170 Fahrenheit. It may be located in the fan discharge duct 37 so as to be responsive to the air temperature immediately downstream of the motor. The selection of the temperatures at which the thermostatic switch closes is of course related to the temperature-motor load representation of FIG. 8. When the motor is idling, that is to say, when there is no water circulation load imposed on it, its temperature is about 160, whereas under full-load when the motor is recirculating water, the motor temperature is about 210 Fahrenheit. Therefore, I provide a thermostat which operates suitably within these no-load and full-load temperatures. As the motor approaches its loaded condition, the thermostatic switch 8i? closes to set up the obvious-secondary circuit, bypassing the cam operated switch 65. At the completion of the final rinsing operation as established by the cam lobe 62.1 moving switches 65 and 68 to opencircuit position, the motor temperature is still at substantially its full load temperature condition, whereupon the motor energizing circuit is completed by way of the thermostatic switch 80, as is apparent in FIG. 7. It will be obvious, of course, that the opening of switches 68 and 70 has deenergized the inlet valve solenoid '77.

The dishwasher cycle is then in its drying stage, wherein air which has been heated by passage over the motor is brought into the dishwasher tub and vented therefrom through the rear vent passage 5. The motor temperature gradually diminishes towards its no-load state, at which position the thermostatic switch 3t opens to signify the end of the full dishwashing and drying cycle.

As an alternative location of the thermostat for the supplemental motor circuit, I have noted in FIG. 2 that a thermostat 81 is located in the outlet duct from the dishwasher tub, whereby the motor circuit will be interrupted when the drop in temperature of the air passing through the dishwasher vent signifies that the drying operation is completed. In this arrangement the thermostat 81 would be calibrated to close as the temperature of the exhaust air approaches that of the hot water used for washing dishes which, in the average household, is of the order of to degrees Fahrenheit. In view of the fact that air circulation into and through the tub is continuous, the thermostat will continue to be responsive to the elevated air temperature, and will remain closed. Following the opening of switches '65 and 66 and 68 and 70, the temperature .of the dish load will drop because of evaporation of the water in the tub, and, of course, the motor is operating under no-load conditions. When the discharging air temperature drops to a predetermined low valuefor example, 110 F .the thermostat 81 will open to signify the end of the operation.

The heat generated by the motor may be used to additional practical advantage by including a dishwarming bypass circuit, as indicated by the conductors 82, 33, and switch 84, which form a shunt around the thermostat 81, FIG. 7. When dishes are to be warmed in preparation of use, they are suitably racked in the tub, the door closed to close the switch 73, and switch 84 closed. This switch may be of the conventional pushbutton operated ratchet type, in which the pushbutton indexes the switch from oii, to on, to off, etc. A pilot light 85 may be included to indicate that dishwarming is in progress.

The fan load on the motor is relatively minor. I have found, for example, that efiective dish heating and drying is accomplished by a fan dischar ing 35 cubic feet of air per minute, at a static pressure head of the order of one-half inch of water.

While there has been described what is at present thought to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

I claim as my inventionf 1. Dishwashing apparatus comprising:

a single tub to receive articles to be washed and dried;

means for admitting Water into said tub;

a pump having inlet and outlet conduits communicating with said tub for recirculating the water content of said tub over the articles therein to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

duct means communicating between said fan and said tub for conveying the heated air discharge from said fan into said tub;

a first circuit for energizing said motor;

means for maintaining said first circuit to motor energizing condition only for a period representing a predetermined duration of a water circulation operation;

a second circuit in paraliel with said first circuit for energizing said motor;

a switch in said second circuit;

and an actuator for said switch, said actuator closing said switch in response to fan air temperature representative of operation of the motor under a water circulation load and opening said switch following a predetermined cooldown of said fan air temperature, whereby operation of said motor and fan continues for an interval following the end of the water circulation operation, to expedite drying of said articles.

2. Dishwashing apparatus according to claim 1, in

which said motor is of the shaded pole type.

3. Dishwashing apparatus according to claim 2, in which said fan comprises a blower wheel mounted on a shaft of said motor and a fan housing including a shroud enveloping said motor to enforce air flow thereover to abstract heat therefrom.

4. Dishwashing apparatus comprising:

a tub to receive articles to be washed;

means for admitting water into said tub;

a pump having inlet and outlet conduits communicating with said tub for recirculating the water content of said tub over the articles therein to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

duct means communicating between said fan and said tub for conveying the heated air discharge from said fan into said tub;

a first circuit for energizing said motor;

means for maintaining said first circuit in motor energizing condition only for a period representing a predetermined duration of a water circulation operation;

a second circuit for energizing said motor;

a switch in said second circuit;

and an actuator for said switch, said actuator closing said switch to provide concurrently closed first and second motor energizing circuits in response to fan air temperature representative of operation of the motor under a water circulation load and opening said switch following an interval of operation of said motor under no water circulation load, whereby operation of said motor and fan continues for a time period following the end of the water circulation operation, to expedite drying of said articles.

5. Dishwashing apparatus comprising:

a tub to receive articles to be washed;

means for admitting water into said tub;

a pump having inlet and outlet conduits communicating with said tub for recirculating the water content of said tub over the articles therein to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

duct means communicating between said fan and said tub for conveying the heated air discharge from said fan into said tub;

a first circuit for energizing said motor;

a switch in said circuit;

means including a cam for operating said switch to closed condition to energize said motor prior to a water circulation operation and later to open said switch at the end of a desired water circulation operation;

a second circuit for energizing said motor;

a switch in said second circuit;

and an actuator for said second switch, said actuator closing said switch to provide concurrently closed first and second motor energizing circuits in response to fan air temperature representative of operation of the motor under a water circulation load, and opening said switch following the reduction of said fan air temperature typifying operation of said motor under load conditions at the end of said water circulation operation, whereby operation of said motor and fan continues for a time period following the end of the water circulation operation to expedite drying of said articles.

6. Dishwashing apparatus comprising:

a tub to receive articles to be washed;

valve means for admitting water into said tub;

a pump operatively associated with said tub for recirculating the water content over the articles to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

means including air ducts into and out of said tub in air flow relation to said fan for circulating warm air from said motor through said tub to facilitate drying of the articles therein;

a first circuit for conjointly energizing said motor and said valve means;

switch means in said circuit;

means following a desired interval of energization of said motor and valve means for opening said switch to interrupt said circuit;

means for evacuating said tub of the Water content thereof prior to opening said switch;

a second circuit for energizing said motor independen ly of said valve means;

a switch in said second circuit; and

means responsive to a first motor temperature to close said second switch to establish a motor energizing circuit in parallel with said first circuit to continue operation of said motor after said first switch is opened, and responsive to a substantially lower motor temperature to open said second switch.

7. Dishwashing apparatus comprising:

a tub to receive articles to be washed;

valve means for admitting water into said tub;

a pump operatively associated with said tub for recirculating the water content over the articles to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

an air flow system including air ducts into and out of said tub in air flow relation to said fan for circulating warm air from said motor through said tub to facilitate drying of the articles therein;

a first circuit for conjointly energizing said motor and said valve means;

switch means in said circuit;

means following a desired energization of said motor and valve means for opening said switch to interrupt said motor circuit;

means for evacuating said tub of the water content thereof immediately prior to opening said switch;

a second circuit for energizing said motor to the exclusion of said valve means;

a switch in said second circuit; and

temperature sensitive means responsive to a first level of temperature in said air flow system to close said second switch to establish a motor energizing circuit in parallel with said first circuit to continue operation of said motor after said first switch is opened, and responsive to a substantially lower temperature in said air flow system to open said second switch.

8. Dishwashing apparatus according to claim 7, in which said thermostat is located in proximity to said fan to sense the temperature of air discharging therefrom.

9. Dishwashing apparatus according to claim 7, in which said thermostat is located Within the air :duct leading from said tub to sense the temperature of air discharging from said tub.

.10. Dishwashing apparatus comprising:

a tub to receive articles to be Washed;

valve means for admitting Water into said tub;

a pump operatively associated with said tube for recirculating the water content over the articles to wash the same;

an electric motor for driving said pump;

a fan powered by said motor for circulating air over said motor for cooling the same;

an air flow system including air ducts into and out of said tub in air flow relation to said fan for circulating warm air from said motor through said tub to facilitate drying of the articles therein;

a first circuit for conjointly energizing said motor and said valve means;

switch means in said circuit;

means following a desired interval of energization of said motor and valve means for opening said switch to interrupt said circuit;

means for evacuating said tub of the Water content thereof immediately prior to opening said switch;

a second circuit for energizing said motor to the exclusion of said valve means;

a switch in said second circuit; and

means for closing said second switch to establish a motor energizing circuit in parallel with said first circuit to continue operation of said motor after said first switch is opened, said means being responsive to a predetermined temperature of air in said air flow system to open said second switch,

11. Dishwashing apparatus comprising:

a single t-ub to contain articles to be washed and dried;

means for introducing water into said tub;

means for circulating Water within the tub for washing articles contained therein;

a motor directly connected thereto for energizing said Water circulation means;

means for concurrently introducing water into said tub and energizing said motor;

means independent of the operation of said motor for delaying operation of said Water circulation means until after a substantial accumulation of Water in said tub;

means for heating air by abstraction of heat from said motor during operation thereof; and

fan means powered by said motor and communicating between said air heating means and said tub for discharging said heated air into said tub continuously during the operation of said motor.

12. Dishwashing apparatus comprising:

a single tube to contain articles to be washed and dried;

electrically energized means for introducing water into said tub;

means for circulating water within the tub for washing articles contained therein;

a motor for energizing said water circulation means;

means for energizing said water inlet means and said motor;

means for delaying operation of said Water circulation means until after an initial period of operation of said motor;

means for heating air by abstraction of heat from said motor during operation thereof; and

fan means powered by said motor and communicating between said air heating means and said tub for discharging said heated air into said tub at all times during the operation of said motor.

References Cited in the file of this patent UNITED STATES PATENTS 1,658,413 

11. DISHWASHING APPARATUS COMPRISING: A SINGLE TUB TO CONTAIN ARTICLES TO BE WASHED AND DRIED; MEANS FOR INTRODUCING WATER INTO SAID TUB; MEANS FOR CIRCULATING WATER WITHIN TUB FOR WASHING ARTICLES CONTAINED THEREIN; A MOTOR DIRECTLY CONNECTED THERETO FOR ENERGIZING SAID WATER CIRCULATION MEANS. MEANS FOR CONCURRENTLY INTRODUCING WATER INTO SAID TUB AND ENERGIZING SAID MOTOR; MEANS INDEPENDENT OF THE OPERATION OF SAID MOTOR FOR DELAYING OPERATION OF SAID WATER CIRCULATION MEANS UNTIL AFTER A SUBSTANTIAL ACCUMULATION OF WATER IN SAID TUB MEANS FOR HEATING AIR BY ABSTRACTION OF HEAT FROM SAID MOTOR DURING OPERATION THEREOF; AND FAN MEANS POWERED BY DAID MOTOR AND COMMUNICATING BETWEEN SAID AIR HEATING MEANS AND SAID TUB FOR DISCHARGING SAID HEATED AIR INTO SAID TUB CONTINUOUSLY DURING THE OPERATION OF SAID MOTOR. 